AGFA Drystar 5500, Reference Manual

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151
2900H EN 20071108 Advanced operation (Key-operator mode)
D
RYSTAR
5500/5503 R
EFERENCE MANUAL
Performing the Weekly QC tests for general radiography applications
(DT 2 B and DT 2 C)
Spatial Resolution, Artifact Test and Low Contrast Visibility
To identify artifacts and verify spatial resolution you must perform the
following test weekly or as needed for troubleshooting image quality
problems.
1
First, print out the QC general radiography test image. Refer to ‘Performing the
daily QC test for general radiography applications (DT 2 B and DT 2 C)’ on
page 149 .
2
Check the QC general radiography test image visually for artifacts: no
significant disturbing artifacts should be visible.
3
Check the spatial resolution.
The test film also shows three squares which each contains an oval. These 3 ovals
contain 3 groups, each having 5 dots. All five dots of each group must be visible with a
magnifying glass. The smallest cluster of 5 dots is only visible if the viewing conditions
are good.
4
Check the Low Contrast Visibility at both the high (100 / 95%) and low end
(0 / 5%) of the density scale. You should be able to see the circle in the square
(refer to item 1 on the
‘QC general radiography test image’ on page 146 ) and the
upper circle (refer to item 2 on the ‘QC general radiography test image’ on
page 146 ).
5
Record these values on Chart 3 (‘Drystar 5500/5503 Artifacts and Spatial
Resolution Control Chart’). Refer to
‘Charts for general radiography QC’ on
page 242 .
Good viewing conditions are important for the correct interpretation of
both diagnostic and test images. Make sure that the light box intensity
(luminance) is between 2000 and 4000 cd/m² (4500 and 6500 °K) for
general radiography. Use a magnifying glass and use shutters to collimate.
Make sure the ambient light is low.
In case of significant artifacts, insufficient spatial resolution or failure of
any other recommended QC tests, the cause of the problem must be
identified, and corrective action must be taken before the Drystar 5500
can be used for any further clinical imaging.
Refer to ‘Maintaining image quality and resolving Image quality problems’ on
page 220 and ‘Preventive maintenance schedule’ on page 186 , or call your
local Agfa service organization for assistance.